"Tried to enjoy @ladygaga's performance, was distracted by the flab on her stomach swinging around," tweeted one viewer, Nathan @negans_swing.

Others came to her defense. "Guys making fun of Lady Gaga's 'muffin top' is the reason why girls have so many body image issues," wrote Twitter user Alexa Morgan.

The "Bad Romance" singer said in 2012 that she had suffered from anorexia and bulimia since she was 15 after being criticized at that time for apparently putting on weight.

Gaga's halftime performance at the National Football League championship game between the New England Patriots and the Atlanta Falcons was a high energy medley of some of her biggest hits. The show mixed patriotism with anthems to inclusion, and drew widespread praise.

Sales of her albums and singles soared 1,000 percent after the show, according to NielsenMusic. Lady Gaga sold about 150,000 digital albums and songs on Sunday, compared to about 15,000 a day prior, Nielsen said.

She also announced a U.S. and European tour, starring in August, and will perform at the Grammys in Los Angeles on Sunday, although she is not nominated this year.